Medzhybizh Castle (Ukrainian: Меджибі́зький замок, Medzhybiz'kyi zamok), built as a bulwark against Ottoman expansion in the 1540s, became one of the strongest fortresses of the Crown of the Kingdom of Poland in Podolia. It is situated at the confluence of the Southern Bug and Buzhenka rivers, in the town of Medzhybizh (Polish: Międzybuż), Ukraine.